Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!aramis.rutgers.edu!paul.rutgers.edu!jac
From: jac@paul.rutgers.edu (Jonathan A. Chandross)
Newsgroups: comp.lang.c
Subject: Re: Odd question re: extern vs. static
Keywords: extern, static, name clash
Message-ID: <Jul.21.17.30.08.1989.5518@paul.rutgers.edu>
Date: 21 Jul 89 21:30:08 GMT
References: <12878@bloom-beacon.MIT.EDU>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 41

scs@adam.pika.mit.edu (Steve Summit)
> The following fragment looks illegal, and probably is:
>	extern int f();
>	static int f;

Nope.  It has worked in pcc based compilers for years.  gcc breaks on 
this, however.

> Marking a file-scope symbol "static" is supposed to make it
> private; to protect it from interfering with global variables in
> other source files.  The problem here is essentially that a
> symbol from another source file is interfering with the local,
> static symbol.

I take a different, more modular, approach to declaring external
functions in a header file:

	#define	EXPORT
	#define	LOCAL	static

	EXPORT int foo()
	{
	extern	float	bar();
		....
	}

	LOCAL float bar()
	{
		....
	}

The point is that I don't want to worry in foo() where bar() is
defined; that is, in this module or in some other module.  And yet
I want the modularity of declaring bar in each function where it
is used, not once per file.  Incidentally, the same thing goes for
global variables.


Jonathan A. Chandross
Internet: jac@paul.rutgers.edu
UUCP: rutgers!paul.rutgers.edu!jac